1S51.] 287 



Whole length from 2 to 4 lines ; breadth l-6th line. 



Habitation. In ditches and ponds in the neighborhood of Philadelphia. 



2. Stylaria fossularis, Leidy. 



Body of two segments, composed of 24 annuli in the first, 22 to the last. Podal 

 spines 5 to 7 in each fasciculus. Setas commencing after the fifth annulus, usually 

 double, to l-66th in. long. Upper lip broad, demi-oval, compressed, not 

 emarginate, with a cylindroid, flexible, proboscidiform appendage the l-33d in. 

 long projecting from its summit. Eyes two, transverse, one on each side of the 

 mouth. Pharynx capacious, extending to the 4th annulus ; oesophagus cylindroid, 

 tortuous, extending to the 7th annulus. 



Whole length 4i lines ; breadth l-6th line. 



Habitation. Found with the preceding. 



ANELCODISCUS, Gemts novum. 

 Body cylindroid, smooth, posteriorly terminated by a cordiform, retractile 

 acetabular disk. Mouth and anus terminal. Intestine simple, straight. 



1. Anelcodiscus PELLUciDus, Leidy. 



Body cylindroid, colorless, transparent ; anteriorly rounded, obtuse ; poste- 

 riorly spreading into a cordiform disk for attachment. Disk retractile : when 

 retracted, the body becoming dilated oval in the middle and the posterior part 

 doubly intussuscepted. 



Length 1-lOOth in.; breadth 1-lOOOth inch. 



Habitation. Parasitic within the intestine oi Stylaria fossularis. 



Remarks. From the translucency of ^the last mentioned worm, its parasite 

 may be seen within the intestine attached to the mucous membrane by means of 

 its posterior cordiform disk. While attached it alternately retracts its body with 

 a jerk, and then lengthens itself; in the former movement the posterior third of 

 the body becoming doubly intussuscepted, so as to have the appearance of a dou- 

 ble articulation. When detached the same movements take place, but in that of 

 retraction the cordiform disk is entirely drawn within the animal's body. More 

 details of this curious parasite I did not obtain, for, although I saw three, and 

 removed them from the intestine of the Stylaria, yet their movements were so 

 active I could not study them to advantage, and to quiet them I tried a minute 

 portion f the vapour of chloroform, which instantly killed them, but at the same 

 moment they underwent total destruction. Since then I have not been able to 

 examine others. 



GREGARINA, Dufour. 



1. Gregarina Scarabei relicti, Leidy. 



Gregarina, Leidy: Pr. A. N. S. v, 208. Found in the larva of Scarabeus 

 relictus. 



EMEA, Leidy: Pr. A. N. S. v, 125. 



Characteribus reformatis. Body linear, compressed. Head continuous with 

 the body, with two lenticular depressions upon each side. Mouth infero-termi- 

 nal. (Esophagus styliferous. Eyes 4 to 6 anterior. Fresh water Nemertinea. 



